CSE 142 Homework 4 (allisonobourn.com)CSE 142 Homework 4 1 of 4 CS 132, Winter 2022 Programming Assignment #4: Anagrams (20 points) Due Tuesday, February 8, 2022, 11:59 PM This program focuses on recursive backtracking. Turn in files named Anagrams.h and Anagrams.cpp from the Project section of the course web site. You will need your LetterInventory files from project 3 and support files anagramMain.cpp and various dictionary text files. All of the instructor provided support files as well as empty files to copy your project 3 code into are included in the starter zip linked on the Projects page of the course website. Anagrams: An anagram is a word or phrase made by rearranging the letters of another word or phrase. For example, the words "midterm" and "trimmed" are anagrams. If you ignore spaces and capitalization and allow multiple words, a multi-word phrase can be an anagram of some other word or phrase. For example, the phrases "Clint Eastwood" and "old west action" are anagrams. In this assignment, you will create a class called Anagrams that uses a dictionary to find all anagram phrases that match a given word or phrase. You are provided with a client program anagramMain that prompts the user for phrases and then passes those phrases to your Anagrams object. It asks your object to print all anagrams for those phrases. Below is a sample log of execution, wrapped into two columns (user input is underlined): Welcome to the CS 132 anagram solver. What is the name of the dictionary file? dict1.txt Phrase to scramble (Enter to quit)? barbara bush All words found in "barbara bush": [abash, aura, bar, barb, brush, bus, hub, rub, shrub, sub] Max words to include (Enter for no max)? [abash, bar, rub] [abash, rub, bar] [bar, abash, rub] [bar, rub, abash] [rub, abash, bar] [rub, bar, abash] Phrase to scramble (Enter to quit)? john kerry All words found in "john kerry": [he, her] Max words to include (Enter for no max)? Phrase to scramble (Enter to quit)? hairbrush All words found in "hairbrush": [bar, briar, brush, bus, hub, huh, hush, rub, shrub, sir, sub] Max words to include (Enter for no max)? 2 [briar, hush] [hush, briar] Phrase to scramble (Enter to quit)? george bush All words found in "george bush": [bee, beg, bog, bogus, bough, brush, bug, bugs, bus, egg, ego, erg, go, goes, gorge, gosh, grub, gush, he, her, here, hog, hose, hub, hug, rub, she, shrub, shrug, sub, surge] Max words to include (Enter for no max)? 0 [bee, go, shrug] (continued on right) [bee, shrug, go] [bog, he, surge] [bog, surge, he] [bogus, erg, he] [bogus, he, erg] [bug, erg, hose] [bug, goes, her] [bug, her, goes] [bug, hose, erg] [bugs, ego, her] [bugs, go, here] [bugs, her, ego] [bugs, here, go] [bus, erg, go, he] [bus, erg, he, go] [bus, go, erg, he] [bus, go, he, erg] [bus, gorge, he] [bus, he, erg, go] [bus, he, go, erg] [bus, he, gorge] [egg, hose, rub] [egg, rub, hose] [ego, bugs, her] [ego, grub, she] [ego, her, bugs] [ego, she, grub] [erg, bogus, he] [erg, bug, hose] [erg, bus, go, he] [erg, bus, he, go] [erg, go, bus, he] [erg, go, he, bus] [erg, go, he, sub] [erg, go, sub, he] [erg, goes, hub] [erg, he, bogus] [erg, he, bus, go] [erg, he, go, bus] [erg, he, go, sub] [erg, he, sub, go] [erg, hose, bug] [erg, hub, goes] ... (full output is on web site) 2 of 4 Implementation Details: Your Anagrams class must have the following public constructor and member functions: Anagrams(vector
& dictionary) In this constructor you should initialize a new anagram solver over the given dictionary of words. You may assume that the words in the vector are in alphabetical order. Do not modify the vector passed to your constructor. vector getWords(string& phrase) In this member function you should return a vector containing all words from the dictionary that can be made using some or all of the letters in the given phrase, in alphabetical order. For example, if your anagram solver is using the dictionary corresponding to dict1.txt and you are passed the phrase "Barbara Bush", you should return a vector containing the elements [abash, aura, bar, barb, brush, bus, hub, rub, shrub, sub]. void print(string& phrase) In this member function you should use recursive backtracking to find and print all anagrams that can be formed using all of the letters of the given phrase, in the same order and format as in the example log on the previous page. For example, if your anagram solver is using the dictionary corresponding to dict1.txt and you are passed the phrase "hairbrush", your member function should produce the following output: [bar, huh, sir] [bar, sir, huh] [briar, hush] [huh, bar, sir] [huh, sir, bar] [hush, briar] [sir, bar, huh] [sir, huh, bar] An empty string should generate no output. void print(string& phrase, int max) In this member function you should use recursive backtracking to find and print all anagrams that can be formed using all of the letters of the given phrase and that include at most max words total, in the same order and format as in the example log on the previous page. For example, if your anagram solver is using the dictionary corresponding to dict1.txt and this member function is passed a phrase of "hairbrush" and a max of 2, your member function should produce the following output: [briar, hush] [hush, briar] If max is 0, print all anagrams regardless of how many words they contain. For example, if using the same dictionary and passed a phrase of "hairbrush" and a max of 0, the output is the same as that shown earlier on this page with no max. You should throw a string exception if the max is less than 0. An empty string should generate no output. The provided anagramMain program calls your member functions in a 1-to-1 relationship, calling getWords every time before calling print. But you should not assume any particular order of calls by the client. Your code should still work if the member functions are called in any order, any number of times. Recursive Algorithm: Generate all anagrams of a phrase using recursive backtracking. Many backtracking algorithms involve examining all combinations of a set of choices. In this problem, the choices are the words that can be formed from the phrase. A "decision" involves choosing a word for part of the phrase and recursively choosing words for the rest of the phrase. If you find a collection of words that use up all of the letters in the phrase, it should be printed as output. 3 of 4 Part of your grade will be based on efficiency. One way to implement this program would be to consider every word in the dictionary as a possible "choice." However, this would lead to a massive decision tree with lots of useless paths and a slow program. Therefore, for full credit, to improve efficiency when generating anagrams for a given phrase, you must first find the collection of words contained in that phrase and consider only those words as "choices" in your decision tree. You should also implement the second print member function so that it backtracks immediately once it exceeds the max. The following diagram shows a partial decision tree for generating anagrams of the phrase "barbara bush". Notice that some paths of the recursion lead to dead ends. For example, if the recursion chooses "aura" and "barb", the letters remaining to use are [bhs], and no choice available uses these letters, so it is not possible to generate any anagrams beginning with those two choices. In such a case, your code should backtrack and try the next path. One difference between this algorithm and other backtracking algorithms is that the same word can appear more than once in an anagram. For example, from "barbara bush" you might extract the word "bar" twice. LetterInventory Class: An important aspect of simplifying the solution to many backtracking problems is the separation of recursive code from code that manages low-level details of the problem. We have seen this in the Maze example. You are required to follow a print("barbara bush"); ... choices: [abash, aura, bar, barb, brush, bus, hub, rub, shrub, sub] chosen: [] letters to use: [aaabbbhrrsu] choices: [abash, aura, bar, barb, brush, bus, hub, rub, shrub, sub] chosen: [abash] letters to use: [abbrru] choices: [abash, aura, bar, barb, brush, bus, hub, rub, shrub, sub] chosen: [aura] letters to use: [abbbhrs] ... choices: [abash, aura, bar, barb, brush, bus,